20091
Longitudinal Development of Preferential Attention to Biological Motion in Infants at Low and High Risk for Developing ASD

Thursday, May 14, 2015: 5:30 PM-7:00 PM
Imperial Ballroom (Grand America Hotel)
L. Olson1, R. D. Sifre2, S. Shultz3, W. Jones4 and A. Klin4, (1)Marcus Autism Center, Children's Healthcare of Atlanta and Emory University School of Medicine, Atlanta, GA, Atlanta, GA, (2)Marcus Autism Center, Emory University School of Medicine, Children's Healthcare of Atlanta, Atlanta, GA, (3)Department of Pediatrics, Marcus Autism Center, Children's Healthcare of Atlanta, Emory University, Atlanta, GA, (4)Marcus Autism Center, Children's Healthcare of Atlanta and Emory University School of Medicine, Atlanta, GA
Background: Preferential attention to biological motion is typically present in human infants shortly after birth and plays a key role in facilitating filial attachment and guiding social interaction (Simion et al., 2007).  In contrast, absence of preferential attention to biological motion in 24-month-olds with ASD (Klin et al., 2009) suggests a disruption of normative social engagement. Little is known, however, about the longitudinal development of preferential attention to biological motion in either TD or ASD populations. Knowledge thereof would be critical in understanding when deviations are first observed in ASD and what their developmental consequences may be.

Objectives: To measure the development of preferential attention to biological motion from 2-24 months in infants at high-risk (HR) and low-risk (LR) for ASD. 

Methods: 88 LR (49 male) and 95 HR (67 male, 50%>12 months) infants were shown point-light biological motion animations as in Klin et al. (2009). An upright point-light animation was presented on one half of the screen, with the inverted version playing on the other half in reverse order. Piloting revealed that trials lasting <30sec failed to elicit interstimulus shifting in young infants; as a result, we increased trial time by playing two unique animations in succession (referred to as part 1 and part 2). Eye-tracking data, collected at months 2, 3, 4, 5, 9, 15, and 24, were used to calculate percentage of fixation time during the whole trial, part 1, and part 2. 

Results: Analyses of percent fixation during the whole trial revealed that at 15 months both LR (M(SD) = 55.8(9.4)%, t(16) = 2.55, p<0.05) and HR infants (M(SD) = 58.2(9.2)%, t(24) = 4.52, p<0.05) have a preference for the upright figure that increases at 24 months, (M(SD) = 63.0(9.5)%, t(28) = 7.33, p<0.05) (M(SD) = 62.6(7.4)%, t(22) = 7.96 p<0.05). Analyses of percent fixation during part 2 of the trial revealed that LR and HR infants have a preference for the upright figure beginning at 3 months (M(SD) = 57.9(19.4)%, t(31)= 2.32,  p<0.05)  (M(SD) = 57.6(19.5)%, t(34) = 2.32, p<0.05), an effect that remains robust at 4, 5, 9, 15, and 24 months (all p’s <0.05) in TD infants. An absence of preferential attention to biological motion was observed at 2 months in LR and HR infants. 

Conclusions: Our results replicate earlier findings of preferential attention to biological motion in 24-month-old TD infants and map the trajectory of this preference during the first two years of life. The absence of preferential attention to biological motion at 2 months, followed by preference at 3 months and thereafter, matches the existing literature regarding preferential attention to faces, which is present at birth but declines at 4-6 weeks of age before re-emerging at 2-3 months. The current findings provide evidence of a similar transition in orienting to biological motion, and highlight this developmental period as a critical focus for future research into the unfolding of social disability in ASD (Klin, Shultz, Jones, 2014). Future analyses will examine early departures from normative trajectories in infants later diagnosed ASD.

See more of: Early Development (<48 months)
See more of: Early Development (< 48 months)